There is a way in which a design like Spacecub could do VTOL without computers. Engineers working on the turboprop delta wing "Pogo" plane back in the fifties concluded landings would go from nightmarish to merely difficult if the pilot were in a pod in the vertical stabilizer so that during landings he was standing on his feet instead of on his back looking over his shoulder. If the rocket motors in the Spacecub were above (forward of) the center of gravity it would automatically be stable in hover (like the Bell rocket backpack) and in the early phases of climb (until the control surfaces had enough airspeed to take over).